The present invention relates to a diaphragm for acoustic equipment. More particularly, the present invention relates to a diaphragm for acoustic equipment having superior acoustic characteristics as a diaphragm for speakers and microphones because of its higher hardness, higher strength, higher elasticity and lighter weight compared with the conventional diaphragm materials.
In general, a diaphragm for speakers and the like meets desirably the following conditions:
(1) Its density is small; PA1 (2) Its Young's modulus is small; PA1 (3) Its propagation velocity of longitudinal waves is high; PA1 (4) Its inner vibration loss is suitably large.
Besides, the formula EQU V=(E/.rho.).sup.1/2
(wherein, V: sound velocity; E: Young's modulus; .rho.: density) requires a material of small density and high Young's modulus in order to increase the sound velocity.
Conventionally, as acoustic diaphragms having high Young's modulus, those using light metals such as aluminum titanium, magnesium, beryllium, boron, etc. are well-known.
However, acoustic diaphragms using aluminum, titanium, magnesium, etc. have no satisfactory specific Young's modulus E/.rho., and acoustic diaphragms using beryllium, boron, etc. have very large specific Young's modulus, but these materials are very expensive and extremely difficult to work industrially, which results in a very high cost as compared with those using other materials.